Geometric and oceanographic controls on melting beneath Pine Island Glacier
Observations beneath the floating section of Pine Island Glacier have revealed the presence of a subglacial ridge which rises up to 300 m above the surrounding bathymetry. This topographic feature probably served as a steady grounding line position until sometime before the 1970s, when an ongoing ph...
Published in: | Journal of Geophysical Research: Oceans |
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ftnerc:oai:nora.nerc.ac.uk:503545 2023-05-15T16:41:52+02:00 Geometric and oceanographic controls on melting beneath Pine Island Glacier De Rydt, J. Holland, P.R. Dutrieux, P. Jenkins, A. 2014-04-15 text http://nora.nerc.ac.uk/id/eprint/503545/ https://nora.nerc.ac.uk/id/eprint/503545/1/jgrc20646.pdf http://onlinelibrary.wiley.com/doi/10.1002/2013JC009513/abstract en eng Wiley https://nora.nerc.ac.uk/id/eprint/503545/1/jgrc20646.pdf De Rydt, J.; Holland, P.R. orcid:0000-0001-8370-289X Dutrieux, P. orcid:0000-0002-8066-934X Jenkins, A. orcid:0000-0002-9117-0616 . 2014 Geometric and oceanographic controls on melting beneath Pine Island Glacier. Journal of Geophysical Research: Oceans, 119 (4). 2420-2438. https://doi.org/10.1002/2013JC009513 <https://doi.org/10.1002/2013JC009513> Publication - Article PeerReviewed 2014 ftnerc https://doi.org/10.1002/2013JC009513 2023-02-04T19:37:54Z Observations beneath the floating section of Pine Island Glacier have revealed the presence of a subglacial ridge which rises up to 300 m above the surrounding bathymetry. This topographic feature probably served as a steady grounding line position until sometime before the 1970s, when an ongoing phase of rapid grounding line retreat was initiated. As a result, a large ocean cavity has formed behind the ridge, strongly controlling the ocean circulation beneath the ice shelf and modulating the ocean water properties that cause ice melting in the vicinity of the grounding line. In order to understand how melt rates have changed during the various phases of cavity formation, we use a high-resolution ocean model to simulate the cavity circulation for a series of synthetic geometries. We show that the height of the ridge and the gap between the ridge and ice shelf strongly control the inflow of warm bottom waters into the cavity, and hence the melt rates. Model results suggest a rapid geometrically controlled increase of meltwater production at the onset of ice thinning, but a weak sensitivity to geometry once the gap between the ridge and ice shelf has passed a threshold value of about 200 m. This provides evidence for a new, coupled, ice-ocean feedback acting to enhance the initial retreat of an ice stream from a bedrock high. The present gap is over 200 m, and our results suggest that observed variability in melt rates is now controlled by other factors, such as the depth of the thermocline. Article in Journal/Newspaper Ice Shelf Pine Island Glacier Natural Environment Research Council: NERC Open Research Archive Pine Island Glacier ENVELOPE(-101.000,-101.000,-75.000,-75.000) Journal of Geophysical Research: Oceans 119 4 2420 2438 |
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Open Polar |
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Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
English |
description |
Observations beneath the floating section of Pine Island Glacier have revealed the presence of a subglacial ridge which rises up to 300 m above the surrounding bathymetry. This topographic feature probably served as a steady grounding line position until sometime before the 1970s, when an ongoing phase of rapid grounding line retreat was initiated. As a result, a large ocean cavity has formed behind the ridge, strongly controlling the ocean circulation beneath the ice shelf and modulating the ocean water properties that cause ice melting in the vicinity of the grounding line. In order to understand how melt rates have changed during the various phases of cavity formation, we use a high-resolution ocean model to simulate the cavity circulation for a series of synthetic geometries. We show that the height of the ridge and the gap between the ridge and ice shelf strongly control the inflow of warm bottom waters into the cavity, and hence the melt rates. Model results suggest a rapid geometrically controlled increase of meltwater production at the onset of ice thinning, but a weak sensitivity to geometry once the gap between the ridge and ice shelf has passed a threshold value of about 200 m. This provides evidence for a new, coupled, ice-ocean feedback acting to enhance the initial retreat of an ice stream from a bedrock high. The present gap is over 200 m, and our results suggest that observed variability in melt rates is now controlled by other factors, such as the depth of the thermocline. |
format |
Article in Journal/Newspaper |
author |
De Rydt, J. Holland, P.R. Dutrieux, P. Jenkins, A. |
spellingShingle |
De Rydt, J. Holland, P.R. Dutrieux, P. Jenkins, A. Geometric and oceanographic controls on melting beneath Pine Island Glacier |
author_facet |
De Rydt, J. Holland, P.R. Dutrieux, P. Jenkins, A. |
author_sort |
De Rydt, J. |
title |
Geometric and oceanographic controls on melting beneath Pine Island Glacier |
title_short |
Geometric and oceanographic controls on melting beneath Pine Island Glacier |
title_full |
Geometric and oceanographic controls on melting beneath Pine Island Glacier |
title_fullStr |
Geometric and oceanographic controls on melting beneath Pine Island Glacier |
title_full_unstemmed |
Geometric and oceanographic controls on melting beneath Pine Island Glacier |
title_sort |
geometric and oceanographic controls on melting beneath pine island glacier |
publisher |
Wiley |
publishDate |
2014 |
url |
http://nora.nerc.ac.uk/id/eprint/503545/ https://nora.nerc.ac.uk/id/eprint/503545/1/jgrc20646.pdf http://onlinelibrary.wiley.com/doi/10.1002/2013JC009513/abstract |
long_lat |
ENVELOPE(-101.000,-101.000,-75.000,-75.000) |
geographic |
Pine Island Glacier |
geographic_facet |
Pine Island Glacier |
genre |
Ice Shelf Pine Island Glacier |
genre_facet |
Ice Shelf Pine Island Glacier |
op_relation |
https://nora.nerc.ac.uk/id/eprint/503545/1/jgrc20646.pdf De Rydt, J.; Holland, P.R. orcid:0000-0001-8370-289X Dutrieux, P. orcid:0000-0002-8066-934X Jenkins, A. orcid:0000-0002-9117-0616 . 2014 Geometric and oceanographic controls on melting beneath Pine Island Glacier. Journal of Geophysical Research: Oceans, 119 (4). 2420-2438. https://doi.org/10.1002/2013JC009513 <https://doi.org/10.1002/2013JC009513> |
op_doi |
https://doi.org/10.1002/2013JC009513 |
container_title |
Journal of Geophysical Research: Oceans |
container_volume |
119 |
container_issue |
4 |
container_start_page |
2420 |
op_container_end_page |
2438 |
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1766032332658049024 |